Harbour porpoise (Phocoena phocoena) presence, abundance and distribution over the Dogger Bank, North Sea, in winter

2016 ◽  
Vol 97 (7) ◽  
pp. 1455-1465 ◽  
Author(s):  
A.-C. Cucknell ◽  
O. Boisseau ◽  
R. Leaper ◽  
R. McLanaghan ◽  
A. Moscrop
Keyword(s):  
North Sea ◽  
Probability Of Detection ◽  
Harbour Porpoise ◽  
Encounter Rate ◽  
Phocoena Phocoena ◽  
Survey Area ◽  
The West ◽  
Dogger Bank ◽  
The North ◽  
The North Sea

An area in the central North Sea was surveyed in November 2011 in order to estimate the abundance and density of harbour porpoises (Phocoena phocoena). A total of 2833 km of pre-determined trackline were acoustically surveyed, of which 28% included visual effort. The poor sighting conditions during the survey limited visual effort and demonstrated the advantage of using acoustic techniques for studying harbour porpoise in winter months. Absolute abundance and density estimates were calculated from acoustic encounter rates using estimates of probability of detection and mean group size. The density of harbour porpoises in the west of the survey area was almost double that in the east, with UK waters to the south-west of the Dogger Bank having the highest density of the area surveyed. The overall acoustic encounter rate was higher than most other surveys in the North Sea. The mean density across the survey area of 0.63 (95% CI 0.27–1.52) individuals km−2and distribution of porpoises was similar to that documented in the summer suggesting that high abundance of harbour porpoises in the west of the North Sea is not confined to summer months. This information is particularly relevant given plans for the construction of a large offshore wind farm on the UK section of the Dogger Bank; the resulting impacts, including acoustic disturbance from pile driving, will potentially affect substantial numbers of harbour porpoises.

Harbour porpoises (Phocoena phocoena) in north-western France: aerial survey, opportunistic sightings and strandings monitoring

2009 ◽  
Vol 89 (5) ◽  
pp. 1045-1050 ◽  
Author(s):  
J.-L. Jung ◽  
E. Stéphan ◽  
M. Louis ◽  
E. Alfonsi ◽  
C. Liret ◽  
...  
Keyword(s):  
North Sea ◽  
Aerial Survey ◽  
Harbour Porpoise ◽  
Shallow Waters ◽  
Encounter Rate ◽  
English Channel ◽  
Phocoena Phocoena ◽  
The North ◽  
The North Sea ◽  
North Western

The harbour porpoise (Phocoena phocoena) is one of the common small cetaceans of European waters. This discreet and undemonstrative species is strongly represented throughout the cold waters of the northern hemisphere, and is the most abundant cetacean in the North Sea. In the last few years, some observations and studies indicate a shift of harbour porpoise distribution in European waters, from northern regions of the North Sea to the southern North Sea, English Channel and Celtic Sea. This shift may include a comeback around the coasts of France. Harbour porpoises inhabit shelf-waters and are often observed in shallow waters, conditions offered for instance by the coasts of Brittany in north-western France. We used opportunistic sightings, aerial survey and a ten-year strandings database to study the presence of harbour porpoises along the coasts of Brittany. Opportunistic sightings made by non-specialists did not confirm a strong presence of harbour porpoises along the Brittany coasts, most probably because of the undemonstrative behaviour of this cetacean. However, aerial survey and stranding analysis indicate that harbour porpoises have become natural inhabitants of the Brittany coasts once more: 68.6% of cetacean school sightings made during a 1578 km aerial survey of the Brittany coasts concerned harbour porpoises, with an encounter rate of 1.5 individuals per 100 km that peaked to 5.8 per 100 km to the top of the shallow waters of the south-western Western English Channel. The number of harbour porpoise strandings increased each year from 1997 to 2007, making a total of 135 along the coasts of Brittany. Other cetaceans did not show such an increase during the same period. Strandings of harbour porpoises were also characterized by an apparent increase as a proportion in relation to all the cetacean strandings during the months of September to January, by a marked impact of by-catch during winter, and by an almost total absence of stranded calves. The comeback of the harbour porpoise along Brittany coasts is clearly confirmed by our data, and a stable population seems to be established again along the coasts of Brittany. This tends to confirm the shift of the distribution of the species in certain European waters. Long term monitoring, diet and genetic studies are now planned for a better understanding of this shift, and for the effective implementation of a conservation plan.

Identification of the first harbour porpoise (Phocoena phocoena) calving ground in the North Sea

1999 ◽  
Vol 41 (3) ◽  
pp. 225-232 ◽  
Author(s):  
R.P Sonntag ◽  
H Benke ◽  
A.R Hiby ◽  
R Lick ◽  
D Adelung
Keyword(s):  
North Sea ◽  
Harbour Porpoise ◽  
Phocoena Phocoena ◽  
The North ◽  
The North Sea

Cutaneous papillomavirus infection in a harbour porpoise (Phocoena phocoena) from the North Sea

1999 ◽  
Vol 144 (21) ◽  
pp. 592-593 ◽  
Author(s):  
M.-F. Van Bressem ◽  
R. A. Kastelein ◽  
P. Flamant ◽  
G. Orth
Keyword(s):  
North Sea ◽  
Harbour Porpoise ◽  
Phocoena Phocoena ◽  
The North ◽  
Papillomavirus Infection ◽  
The North Sea

I.—On a Collection of Pleistocene Mammals Dredged off the Eastern Coast

1878 ◽  
Vol 5 (3) ◽  
pp. 97-100
Author(s):  
William Davies
Keyword(s):  
North Sea ◽  
Eastern Coast ◽  
Dogger Bank ◽  
The North ◽  
Close Proximity ◽  
The North Sea ◽  
Fine Collection ◽  
Pleistocene Mammals ◽  
The Many ◽  
Private Collections

Of the many private collections of vertebrate fossils found on or off the coast of the Eastern counties, none surpass in palæontological and also in geological interest the fine collection made with much zeal and care by Mr. J. J. Owles, of Yarmouth, inasmuch as the larger portion of the specimens are exclusively the remains of Postglacial Mammals, and were brought up in the fishermen’s dredge, either from, or in close proximity to the well-known Dogger Bank, thus proving conclusively the existence of submerged Pleistocene or Postglacial land lying off the Eastern coast in the North Sea. Prof. Boyd Dawkins is the only author, as far as I am at present aware, who has made any reference to this really valuable series of remains, and then only incidentally in his memoir, “On the Distribution of Postglacial Mammals.”

Population structure of harbour porpoises in the Baltic region: evidence of separation based on geometric morphometric comparisons

2012 ◽  
Vol 92 (8) ◽  
pp. 1669-1676 ◽  
Author(s):  
Anders Galatius ◽  
Carl Christian Kinze ◽  
Jonas Teilmann
Keyword(s):  
Population Structure ◽  
Baltic Sea ◽  
North Sea ◽  
Harbour Porpoise ◽  
Baltic Region ◽  
Geometric Morphometric ◽  
The North ◽  
The North Sea ◽  
The Baltic ◽  
Separate Population

The harbour porpoise is seriously depleted and threatened with extinction in the Baltic Sea. It is usually assumed that Baltic porpoises form a separate population unit, although the evidence for this has been disputed lately. Here, a 3-D geometric morphometric approach was employed to test a number of hypotheses regarding population structure of the harbour porpoise in the Baltic region. 277 porpoise skulls from Denmark, Sweden, Finland, Germany and Poland were measured with a suite of 3-D landmarks. Statistical analyses revealed highly significant shape differences between porpoises from the North Sea, Belt Sea and the inner Baltic Sea. A comparison of the directionalities of the shape vectors between these units found differences that cannot be attributed to a general, continual shape trend going from the North Sea to the inner Baltic Sea. These vectors indicate a morphological adaptation to the specific sub-areas. Such adaptation may be the result of the topographic peculiarities of the area with variable topography and shallow waters, e.g. in the Belt Sea porpoises, there may be a greater reliance on benthic and demersal prey. The present results show that isolation by distance alone is an unlikely explanation for the differences found within the Baltic region and thus support previously reported molecular indications of a separate population within the inner Baltic Sea.

scholarly journals Diel echolocation activity of harbour porpoises (Phocoena phocoena) around North Sea offshore gas installations

2009 ◽  
Vol 66 (4) ◽  
pp. 734-745 ◽  
Author(s):  
Victoria L. G. Todd ◽  
William D. Pearse ◽  
Nick C. Tregenza ◽  
Paul A. Lepper ◽  
Ian B. Todd
Keyword(s):  
North Sea ◽  
Gas Production ◽  
Diel Activity ◽  
Phocoena Phocoena ◽  
Drilling Rig ◽  
The North ◽  
Production Platform ◽  
The North Sea ◽  
Exploration Drilling ◽  
Passive Acoustic

Abstract Todd, V. L. G., Pearse, W. D., Tregenza, N. C., Lepper, P. A., and Todd, I. B. 2009. Diel echolocation activity of harbour porpoises (Phocoena phocoena) around North Sea offshore gas installations. – ICES Journal of Marine Science, 66: 734–745. Echolocation clicks of harbour porpoises (Phocoena phocoena) were detected with T-PODs, autonomous, passive, acoustic-monitoring devices, deployed from an offshore-exploration-drilling-rig and gas-production-platform complex in the Dogger Bank region of the North Sea from 2005 to 2006. Echolocation-click trains were categorized into four phases of the diel cycle: morning, day, evening, and night. Porpoises were present near (<200 m) the platform, and there was a pronounced diel pattern in echolocation activity; the number of porpoise encounters (visits) was greater by night than by day. The number of click trains with a minimum inter-click interval of <10 ms also increased at night. This was confirmed by a comparison of the ratios of feeding buzzes to search-phase clicks (feeding buzz ratios) and an analysis of the changes in pulse-repetition frequencies within each train. A reasonable interpretation of this pattern was that porpoises were feeding below or around the platform at night. The evidence for changes in activity during the morning and evening was less clear, so these may be transitional phases. The pattern of porpoise-echolocation behaviour around this platform is related most probably to the diel activity of their prey. If porpoises cluster regularly around such installations within 500-m shipping exclusion zones, they may be omitted from population surveys. We conclude that offshore installations may play an important role as nocturnal porpoise-feeding stations in an overfished environment, but that further replicated and controlled studies are required. These findings should be taken into consideration during offshore-installation-decommissioning decisions in the North Sea.

scholarly journals First record of the rare crab Asthenognathus atlanticus Monod, 1933 (Crustacea: Brachyura: Varunidae) in the North Sea

2021 ◽  
Vol 50 (3) ◽  
pp. 352-358
Author(s):  
Marco Faasse ◽  
Hendrik Gheerardyn ◽  
Rob Witbaard ◽  
Joël Cuperus
Keyword(s):  
North Sea ◽  
First Record ◽  
Western Mediterranean ◽  
Distribution Range ◽  
Marine Waters ◽  
The West ◽  
The North ◽  
The North Sea ◽  
Northward Expansion ◽  
First Time

Abstract Several species new to the area were collected while monitoring Dutch marine waters using a dredge. The varunid crab Asthenognathus atlanticus Monod, 1933 was recorded for the first time in the North Sea. Until 2008, this relatively rare crab was known from the west coast of Africa and the western Mediterranean to northern Brittany in the north. In recent years, its distribution range has expanded, as indicated by records from the Bay of the Seine and the area around Dieppe-Le Tréport. Our finding from Brown Bank (southern North Sea) indicates a further, northward expansion of its distribution range. We list the hosts with which the crab is associated. Earlier arguments for climate change as an explanation for the northward range expansion are supported.

scholarly journals Why do jellyfish bloom in Norwegian waters and what can be done to recover the ecosystems in the North Sea and on the Norwegian coast?

2017 ◽  
Author(s):  
Johannes Hamre
Keyword(s):  
North Sea ◽  
West Coast ◽  
Trophic Levels ◽  
The West ◽  
Fish Stocks ◽  
Norwegian Coast ◽  
The North ◽  
Key Species ◽  
Wide Range ◽  
The North Sea

The ecosystems with their relationships between fish species and stocks, have been established by evolution for millions of years, but during the last 50 years, the ecosystems in the North Sea and along the Norwegian coast have been changed fundamentally by fisheries. The North Sea mackerel stock has been depleted and its feeding grounds have been invaded by the Western mackerel which spawns west of Ireland. This stock is now very rich in numbers and occupies the North Sea, the Norwegian Sea and the western Barents Sea. If the trend continues, mackerel may outcompete many of the other fish stocks in the area. Traditionally and until the beginning of the 1970s, there was a large stock of sandeel spawning in the North Sea and on the Norwegian coast. Sandeel juveniles was an important food source for a wide range of species, including sea mammals and birds. The fact that this stock has also been overfished, may explain many changes observed in the ecosystem on the west coast of Norway, for example a large reduction in the populations of sea birds. There are several instances where ecosystems shift to sustain jellyfish blooms in response to depletion of forage fish stocks. This was registered in Namibia in the 1990’s, where the pilchard stock was decimated and the biomass of jellyfish soon became overwhelming. On the west-coast of Norway, there are now frequent blooms of jellyfish, yet another indication that a controlling factor is missing in the system, in this case sandeel, which is a key species in the transfer of nutrients from zooplankton to higher trophic levels in the area. In this paper, I give a description of the situation and some suggested measures that should be taken in fisheries management.

scholarly journals Recent Foraminifera from the North Sea (Forties and Ekofisk areas) and the continental shelf west of Scotland

1985 ◽  
Vol 4 (2) ◽  
pp. 117-125 ◽  
Author(s):  
John W. Murray
Keyword(s):  
Continental Shelf ◽  
North Sea ◽  
Standing Crop ◽  
High Energy ◽  
The West ◽  
The North ◽  
Energy Environment ◽  
Bottom Waters ◽  
The North Sea ◽  
Northern North Sea

Abstract. The regions studied are all of mid continental shelf depth (70–145 m) and have bottom waters of normal marine salinity. The North Sea has lower bottom water temperatures than those to the west of Scotland. However, the major difference between the two regions is one of tidal and/or wave energy: the northern North Sea is a low energy environment of muddy sand deposition whereas the sampled part of the continental shelf west and north of Scotland is a moderate to high energy environment of medium to coarse biogenic carbonate sedimentation.The physical differences between the two main areas are reflected in the living and dead foraminiferal assemblages. The northern North Sea is a region of free-living species whereas the continental shelf west of Scotland has immobile and mobile attached species living on firm substrates. The northern North Sea is very fertile and has high standing crop values.The dead assemblages are small in size and very abundant. To the west of Scotland the sea is less fertile, standing crop values are low, the dead assemblages are moderate to large in size and reasonably abundant due to the slow rate of dilution by sediment.

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